Guardant Health’s Shield blood test has already been used by hundreds of thousands of people since its 2025 launch, with the company targeting millions of tests as it works to reach the estimated 54 million Americans who are unscreened or overdue for colorectal cancer screening. The test is increasingly being offered to patients hesitant about colonoscopy, and more than half of those who test positive have gone on to complete a follow-up colonoscopy.
But the next challenge is improving what blood-based screening can detect. In the pivotal study, Shield missed 16.9% of colorectal cancers and had just 13.2% sensitivity for advanced precancerous lesions. Guardant says its next-generation test will look beyond DNA to signals including proteins, lipids, RNA and other metabolites in an effort to improve early-stage and precancer detection. The company is also pursuing a multicancer version covering 10 cancers, potentially using the same blood draw and kit.